Grinders of the tub type are widely used for chipping, breaking or tearing of items or materials which are very difficult to otherwise comminute. The process expends a great deal of mechanical energy and often involves the violent throwing of chips or pieces of varying sizes upwardly out of the tub. For this reason, such grinders are typically trailered to isolated locations such as out in the middle of a large field such that the thrown chips or pieces cannot injure property or bystanders who may come into the danger zone of the grinder which may extend outwardly therefrom several yards. Such precautions may serve their purpose very well, however, the fact remains that workers who feed the materials into the grinder and remove the comminuted product from the area, or who attend to the machinery during its operation must remain in close proximity to the grinder and are thus exposed to considerable danger, regardless of their use of hard hats or the like.